<svg xmlns="http://www.w3.org/2000/svg"
     xmlns:xlink="http://www.w3.org/1999/xlink"
     width="100" height="100">
  <!-- This blue rect should be covered up by the <image> when this SVG is
       loaded as an image by a local document, but not when the document is
       served over HTTP: -->
  <rect width="100" height="100" fill="blue"/>
  <image width="100" height="100"
         xlink:href="lime100x100.png"/>
</svg>
